Disciplines / Research questions

Physics

691 research topics · 2739 questions

Alternative Way of Solving the Ice-Type Models6 questions
  1. Integrable manifolds and commuting transfer matrices of the odd eight-vertex model

    Open for about 8 years
  2. Extending the FPRAS for the six-vertex model with an unwindable constraint function beyond two-by-two-intersection-free circuit decompositions and the b≤1/δb\le 1/\delta regime

    Open for about 4 years
  3. Deriving Bethe equations for the XYZ spin chain from the matrix-product-operator construction

    Open for less than 1 year
  4. Analytic proof of the even-index Yang–Baxter conjectures for descendants of the six-vertex model from the Drinfeld doubles of dihedral group algebras

    Open for about 16 years
  5. Completing the approximation-complexity classification of the six-vertex model: the white region of the disordered phase and the Tutte point T(G;3,3)T(G;3,3) on planar graphs

    Open for about 8 years
  6. Completeness of the homogeneous TT–QQ Bethe ansatz for the eight-vertex model with quasi-periodic boundary conditions on an odd number of sites

    Open for about 11 years
analytic Bethe Ansatz2 questions
  1. Completeness of the Wronskian Bethe ansatz for rational gl(m|n) spin chains in arbitrary highest-weight representations and the exceptional specialisation locus

    Open for about 6 years
  2. Completing the analytical Bethe ansatz for gl(M|N) super-spin chains: the M=N case, non-commuting boundary matrices, and reflection-superalgebra representations

    Open for about 19 years
Andrews–Baxter–Forrester model3 questions
  1. Bosonic finitized character formulas and the CTM recursion for the one-dimensional sums of the 2×22\times2 fused RSOS(m,m′)(m,m') models with m′>2mm'>2m

  2. Massive integrable structure of the off-critical logarithmic minimal models LM(p,p';t)

  3. Complete analysis of the open off-critical RSOS quantum chains: integrable boundaries, open-chain spectra, and reality of the non-Hermitian double-row transfer matrices

ASEP/TASEP2 questions
  1. Full-path-space convergence of multi-type invariant measures and of the ASEP speed process to the stationary horizon

  2. Mixing times and cutoff for the asymmetric simple exclusion process with open boundaries across its three phases (Elboim–Schmid, Conjecture 1.3)

Ashkin–Teller model3 questions
  1. Completing the exact solution of the Ashkin–Teller conformal field theory: the 4-state Potts point, degenerate conformal blocks at rational central charge, and continuation to generic central charge

  2. The SLE(4,g−1,g−1)\mathrm{SLE}(4,\sqrt{g}-1,\sqrt{g}-1) conjecture for Ashkin–Teller parafermionic interfaces and its Schramm-formula test

  3. Microscopic-to-conformal boundary dictionary of the critical quantum Ashkin–Teller chain: non-universal coupling maps, semi-duality-protected level crossing, and four-state Potts asymptotics

Ashkin–Teller self-dual line1 questions
  1. Conformal-field-theory status of transverse-polarized (new) boundary conditions in quantum Potts chains and the transverse-polarized-blob duality beyond the solved endpoints

ballistic transport2 questions
  1. Open extensions of ballistic macroscopic fluctuation theory for the hard-rod gas: slowly varying external potentials, mesoscopic fluctuating hydrodynamics from inhomogeneous states, and the Toda chain

  2. Theory of finite-size validity of integrable hydrodynamics: why very small Toda chains reproduce thermodynamic ballistic correlation profiles

basic hypergeometric functions1 questions
  1. Multi-sum-to-single-sum transformations: other base summations, an underlying WP-Bailey chain, and combinatorial proofs of the embedded Jacobi-type identities (Mc Laughlin 2016)

Baxter QQ operator4 questions
  1. Rigorous foundations of Baxter's T−QT-Q relation for the generic periodic XYZ spin chain: the parameter β\beta, completeness, singular solutions, and Bethe vectors

    Open for about 54 years
  2. Algebraic completion of the Q-operator programme for the XXZ chain at roots of unity: FM-string creation operators, the hidden Onsager-type symmetry, Bethe completeness, and FM-string thermodynamics

    Open for about 5 years
  3. Rigorous QQ-system foundation for SO(2r)\mathrm{SO}(2r) spin chains: operator-level proofs for general representations, Wronskian Bethe completeness, and a DrD_r Baxter TQTQ analogue

    Open for about 6 years
  4. Polynomiality and commutativity of the Q-operator for the open XXZ spin chain with diagonal boundaries (Vlaar-Weston Conjecture 6.3)

    Open for about 6 years
Bazhanov–Baxter three-dimensional lattice model2 questions
  1. Microscopic verification of the M-theory brane construction of the Kapranov-Voevodsky / Bazhanov-Sergeev / Yoneyama 3D lattice model

  2. Critical behavior, scaling limit, and transfer-matrix spectrum of the N-state Bazhanov-Baxter model on the cubic lattice

Bethe wave function3 questions
  1. Ab initio derivation of generalised hydrodynamics from Bethe wave functions: controlling the sum over permutations in the hydrodynamic limit

    Open for about 3 years
  2. Domain of validity of the effective Bethe ansatz for non-integrable spin chains: optimal off-shell states and cost functions, the mechanism of factorized-scattering breakdown, and real-time dynamics

    Open for less than 1 year
  3. Proof of the Kotousov–Lukyanov conjectures for the scaling-limit norms of Bethe states in the critical XXZ Heisenberg chain

    Open for about 7 years
Bethe equations3 questions
  1. Weak string hypothesis for gl(n|m) supersymmetric spin chains: rigorous foundation

    Open for about 15 years
  2. Completing the exact solution of the Izergin-Korepin Gaudin model: Bethe-root structure, eigenstates, and completeness

    Open for about 1 year
  3. Physicality of singular Bethe solutions in the remaining open cases: sufficiency for the higher-spin XXZ chain and eigenstate construction for strange repeated-root solutions

    Open for about 11 years
Completeness of Bethe equations3 questions
  1. Completeness of the Bethe equations for the periodic spin-1/2 XXX Heisenberg chain: proving the counting conjecture

    Open for about 13 years
  2. Completeness and soundness of the off-diagonal Bethe ansatz solution of anisotropic spin-1/2 chains with arbitrary boundary fields: the open XYZ chain

    Open for about 13 years
  3. Completeness of the coordinate Bethe ansatz for the periodic ASEP with tunable interaction (the general-U Bethe equations of Nakerst–Prosen–Haque)

    Open for about 2 years
Bethe lattice magnetization, free energy, and critical behavior2 questions
  1. Low-temperature critical exponents of the Ising model on random trees and locally tree-like random graphs: the susceptibility exponent γ′\gamma' and the specific-heat exponent α′\alpha'

    Open for about 13 years
  2. Rigorous organization of Bethe states and effective evaluation of the Bethe variational formula for spin systems on the Bethe lattice

    Open for about 8 years
Bethe lattice recursion relations2 questions
  1. Invisible-state transmutation thresholds for the q = 3 and q = 4 Potts models beyond mean field: planar random graphs and two-dimensional lattices

    Open for about 13 years
  2. Phase diagram of semiflexible self-avoiding trails with independent crossing and collision weights on the square lattice

    Open for about 9 years
Bethe lattice and Cayley tree3 questions
  1. The infinite-dimensional limit of KPZ surface growth and the upper critical dimension of the KPZ universality class

    Open for about 40 years
  2. Invariant sets of the period-two splitting map and the complete catalogue of periodic Gibbs measures for the q-state Potts model on the Cayley tree

    Open for about 13 years
  3. Classification of weakly periodic Gibbs measures for the two-state hard-core model on Cayley trees: exact multiplicity, extremality, and the (k, i, lambda) phase diagram for normal divisors of index four

    Open for about 12 years
Bethe root density and hole density3 questions
  1. Even-length Bethe strings and the antiferromagnetic vacuum of the all-loop su(2) Bethe equations in planar N=4 supersymmetric Yang-Mills theory

  2. Thermodynamic root-density equation for the two-parameter Lieb–Liniger/Cheon–Shigehara interpolation beyond the non-interacting line

  3. Edge-region 2-string deviations, special-object numerics, and counting integers in the excited-state nonlinear integral equations of the spin-1 XXZ chain

Bethe roots and complex root structure1 questions
  1. Analytic origin and finite-size scaling of the root-organisation rules in the open XXX spin-1/2 chain with non-diagonal boundary fields

    Open for less than 1 year
Bethe state norm4 questions
  1. Explicit finite-size normalization of nested Bethe ansatz eigenfunctions for continuum multicomponent quantum gases

    Open for about 1 year
  2. Rigorous justification of the replica coordinate Bethe ansatz for the log-gamma polymer: Bethe-string norms, completeness, and analytic continuation in replica number

    Open for about 12 years
  3. Norms of Bethe states in the Jaynes-Cummings-Gaudin model: the separated-variable integral versus the Gaudin determinant

    Open for about 19 years
  4. Prove or refute the Gaudin-type determinant norm formula for Bethe eigenstates of the hard-wall Lieb-Liniger model

    Open for about 3 years
Bethe Ansatz for stochastic processes3 questions
  1. Degenerate spectral biorthogonality for string specializations of the q-Hahn coordinate Bethe eigenfunctions

  2. Determinantal and simplified transition-probability formulas for the multi-species ASEP with long-range jumps, and the integrable two-sided long-range extension

  3. Open problems on the spiked spectral boundary of the ASEP: Bethe-root clustering, restricted-cycle random graphs, and Bethe-ansatz completeness

Bethe strings and string hypothesis2 questions
  1. Validity of the string hypothesis for generalized Hubbard models with nonzero Bethe-equation phases

    Open for about 16 years
  2. Unphysical singular solutions of the periodic spin-1/2 XXX Bethe equations: classification, thermodynamic-limit abundance, and why string-hypothesis counting still works

    Open for about 13 years
Bond-dimension extrapolation2 questions
  1. Controlled and scalable variance computation for iPEPS ground states and steady states: cell-size and boundary-dimension requirements, long-distance contraction drift, and direct Liouvillian-norm minimization

  2. Finite bond dimension at two-dimensional quantum criticality in iPEPS: Lifshitz-point convergence, operator content of the truncation geometry, and D as a continuum regulator

bootstrap principle2 questions
  1. Exact structure constants of E-series Virasoro minimal models: the polynomiality conjecture, complete q=18q=18 and q=30q=30 formulae, and the unexplained vanishing of C13,13,13evenC^{even}_{13,13,13} in Ep,30E_{p,30}

  2. Completing the R-matrix bootstrap for the 2d O(N) bosonic model with a boundary

Bosonic/fermionic character representation3 questions
  1. Completing the fermionic MLDE classification of two-dimensional fermionic rational conformal field theories and its dictionary to fermionic modular tensor categories

  2. Spinon-type basis and analytic large-k proof of the spinon character formula for graded parafermions (osp^(1,2)k/u^(1)\widehat{\mathfrak{osp}}(1,2)_k/\widehat{\mathfrak{u}}(1))

  3. Free-fermion realisation of the level-h∨h^{\vee} string functions cρ^ρ^c^{\hat\rho}_{\hat\rho} of sl^(n+1)n+1\widehat{\mathfrak{sl}}(n+1)_{n+1}: Han's Conjectures 2.2 and 2.6 at general rank

boundary SS matrix3 questions
  1. Quantum integrability of the Coulomb-branch open string: the quantum reflection factor and conserved charges of the D3-brane boundary

  2. Modified boundary crossing for non-invertible symmetries beyond regular module categories: breather spectra, non-regular vacua, and boundary RG flows in 1+1 dimensions

  3. Open problems of the R-matrix bootstrap for the 2d O(N) bosonic model with a boundary

boundary crossing-unitarity4 questions
  1. Boundary crossing relations, dressing factors, bound states, and boundary thermodynamics for integrable open spin chains in AdS3/CFT2

  2. Charge-dependent infinite-dimensional reflection matrices in the sine-Gordon model with a boundary: scalar factors, completeness of defect dressing, and classical boundary correspondence

  3. Completing the exact quantum boundary theory of the complex sine-Gordon model on a half line: reflection CDD factors, boundary-pole classification, and boundary-parameter renormalisation

  4. Genuinely integrable boundaries of the 2d O(N) sigma model: closing the mismatch between conformal (M), Lax (U/kappa), and quantum (BYBE) classifications

boundary entropy1 questions
  1. Tracy-Widom TBA for exact g-functions beyond the self-dual sinh-Gordon point: bound states, internal degrees of freedom, excited states, and the SoV normalization

boundary Yang–Baxter equation3 questions
  1. Completing the boundary scattering theory of massive ϕ1,3\phi_{1,3}-perturbed unitary minimal models: the exact ξ\xi–(h,λ^)(h,\hat{\lambda}) UV–IR map, reflection matrices for general Cardy superpositions, and boundary residual quantum-group symmetry

  2. Classification of solutions of the boundary Yang-Baxter equation beyond the rational quasi-classical case: trigonometric K-matrices and non-quasi-classical (singular) K-matrices

  3. K-matrices for type-II graded Satake diagrams: the graded and twisted reflection-equation conjectures for quantum super-spherical pairs

Braid group representation1 questions
  1. Faithfulness of the Bardakov-Bellingeri conjugation representations of surface braid groups on free groups

CDD factor3 questions
  1. Open classification of UV completions of integrable TTˉT\bar{T}-deformed CFTs: admissible CDD factors, remaining spectra, and UV field content

  2. Rigorous convergence of the two-dimensional unitarity iteration and the continuum fate of the CDD fractal

  3. Analyticity, locality and ultraviolet behaviour of fractional-spin CDD deformations of Zn\mathbb{Z}_n-graded S-matrices

corner environment3 questions
  1. Analytic theory of the corner transfer matrix spectrum and deformed corner Hamiltonian for lattice models on hyperbolic lattices

  2. Direct derivation of the surface–corner scaling function Θs,c(x)\Theta_{s,c}(x) and rigorous proof of the series–CFT identity for the critical Ising rectangle

  3. Completing the corner-operator expansion (COE) of critical profiles near corners: the next nonvanishing apex operators and their amplitudes

corner environment contraction3 questions
  1. Open problems for the reduced-cost corner-transfer contraction of infinite PEPS environments: truncation-error control, criticality limits, symmetry and update-scheme integration, and single-layer benchmarking

  2. Corner-transfer-tensor density-matrix renormalization group for three-dimensional classical lattice models: practical realization and the obstruction behind its failure

  3. Error-controlled tensor-network computation of corner magnetization and corner critical exponents

Corner Transfer Matrices7 questions
  1. Origin of the renormalizability structure of corner-transfer-matrix contractions for the kicked 2D quantum Ising Floquet system and its conjectured entanglement transition

    Open for about 10 years
  2. Asymmetric and three-dimensional extensions of the variational corner transfer matrix renormalization group (vCTMRG)

    Open for about 4 years
  3. Equality of the charge(3) and even constraint capacities on the square lattice, and certified two-sided bounds for these non-local two-dimensional constraints

    Open for about 13 years
  4. Robust contraction of infinite two-dimensional tensor networks with non-Hermitian transfer matrices

    Open for about 7 years
  5. Implicit versus explicit truncation in corner-transfer-matrix and corner-tensor simulation of infinite quantum lattice systems: which truncation style is more accurate per computational cost?

    Open for about 14 years
  6. Analytic theory of the corner-transfer-matrix spectrum and corner-Hamiltonian renormalization for classical lattice models on hyperbolic lattices at criticality

    Open for about 19 years
  7. Lattice-level status of the entanglement-spectrum–corner-Hamiltonian correspondence in integrable open spin chains

    Open for about 10 years
Coulomb-gas representation4 questions
  1. Topological lines of the XXZ_q CFT beyond the Coulomb-gas construction: microscopic definition, factorization algebra, modular properties, and embedding into local theories

  2. Coulomb-gas partition functions for multiple SLEs at exceptional parameters: probabilistic, logarithmic-CFT, and lattice interpretation

  3. Free-field resolution and W zero-mode eigenvalue conjectures for W[g^](p,p′)\mathcal{W}[\widehat{g}](p,p') minimal models

  4. Completing the regularization of Dotsenko-Fateev integrals: immersed Pochhammer-type cycles, rigorous screened vertex operators for the BPZ minimal models, and the topology of the doubled integration domains

Origin and mechanism of CP violation and its cosmological connection7 questions
  1. Quantitative baryogenesis from the QCD axion's damped, time-varying strong-CP violation: computing the baryon yield coupled to low-scale baryon-number violation across the axion parameter space

    Open for about 4 years
  2. Determination of the right-handed-neutrino spectrum and the quantitative baryon-asymmetry prediction in the single-CP-phase axion-less solution of the strong CP problem

    Open for about 1 year
  3. Viability and distinguishability of the linked inflation–spontaneous-CP-violation framework of Hashimoto, Risdianto and Suematsu (2021): multi-field dynamics, quantum-gravity-induced U(1) breaking, and the joint viable parameter space

    Open for about 4 years
  4. Quantitative fate of the internal-time-operator CP violation: can it generate the cosmic baryon asymmetry and the neutrino–antineutrino oscillation asymmetries?

    Open for about 4 years
  5. First-principles quantitative viability of electroweak baryogenesis from transient spontaneous CP violation in the 2HDM+a (bubble-wall velocity, dark-matter interplay, and the radiative origin of the CP-breaking phase)

    Open for about 4 years
  6. Viability of the strong-CP-guided parity MLRSM: completing the correlated parameter-space map and the parity domain-wall question

    Open for about 6 years
  7. Group-theoretical CP violation from string theory: UV completion and phenomenological viability of the winding-doublet mechanism

    Open for about 8 years
CTM eigenvalues3 questions
  1. Physical origin of flat corner-transfer-matrix spectra and the renormalizability-entanglement connection in 2D strongly coupled Floquet systems

  2. Unusual corrections to the entanglement entropy of the massive XYZ chain and the character structure of its corner transfer matrix

  3. Two-dimensional constraint capacities: the charge(3)-even equality conjecture and certified corner-transfer-matrix bounds

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